What is the difference between map and struct in Go?

Question

Accepted Answer

**map** — key-value pairs, dynamic. **Struct** — fixed fields, typed.

**Map:**
- Key-value pairs.
- Dynamic keys.
- Reference type.
- No fixed schema.

```go
m := map[string]int{
    "alice": 30,
    "bob": 25,
}

m["charlie"] = 35  // Add new
delete(m, "bob")   // Remove
value, ok := m["alice"]  // Check existence
```

**Struct:**
- Fixed fields.
- Compile-time type checking.
- Value type.
- Fixed schema.

```go
type Person struct {
    Name string
    Age  int
}

p := Person{Name: "Alice", Age: 30}
p.Age = 31  // Modify
```

**When to use:**
- **map** — dynamic keys, unknown structure.
- **struct** — known structure, type safety.

Go: What is the difference between map and struct in Go?